is higher efficiency worth it?

[jp_nc]

We are replacing our existing package unit as part of a remodel/addition. We're going with 2 systems (Trane equipment), one in the basement and one in the attic (2 story house).

This is an older home, built in 1935, so it is not the peak of energy efficiency, to say the least. We've done what we can to improve that, but until we replace the rest of the windows, and get better insulation blown into the walls (brick exterior), I think we are going to have hot and cold spots no matter what type of system we use. Am I wrong? And before you ask why we are doing an addition instead of replacing the windows and adding insulation to the walls; we need the space more than we need perfect comfort. ;-)

Given that, is it really worth the money to go with variable speed furnaces, or even just 2 stage, and 14 SEER AC? Just about anything would be an improvement over what we have now. And going with the VS and the 14 SEER is about 25% more expensive (several thousand dollars) all added up and this project is already going to tax the budget.

So, is it worth it? I've read the marketing material and listened to the HVAC guys but I'm not entirely convinced. Am I missing something? What are the real benefits?

[mark beiser]

You don't say here the house is located, wich is important to being able to answer your question.

If you live someplace where 100 degree summer temperatures are normal, a 14+ SEER system is probably well worth it if you are staying in the house for a number of years.
If you live up north, spending the $ on 14+ SEER AC is probably not a good investment, but a 90%+ furnace would be a wise move.
IMO, get a varriable speed furnace.

[sline-dawg]

Always buy the best you can afford.... How old is the car you drive ??How about your refigerator ?
After this year,2005, the least efficient unit they can make will be 12 seer. You will still be able to buy 10 seer stuff..... if available.
Energy cost will almost certainly rise, so buy the best you can... and fix those windows...
But, hey, I'm just a hvac guy... what do I know.I'll bet you will have nice faucets and tubs.... good luck to you.

[wormy]

Where do you live? (state / general idea)

How big is the house?

What kind of bills did you have before?

What percentage of house are you adding?

How old is your old unit?

Though these questions are not going to give us an
accurate way of answering the questions... but it will
give us a general idea.

Try here...
it may give you a pretty good idea.
http://trane.com/Residential/SelectS...ustomizer.aspx


Variable speed blower.
Advantages include.
Lowers humidity in house. Lower the humidity in summer, and you will feel cooler. So instead of setting your stat at 75 to be comfortable, you might can set it at 78 and feel the same way. This equates to even more effeciency.
Each degree above 75 equates to around 6-9% savings if I remember correctly. This is basicly savings in addition to the 14seer effeciency.

Variable speed blowers are also quieter. Though if your unit is in the attic or in the basement, this may not even be an issue.

The only disadvantage would be replacement cost.
I've got a feeling that it will lower as the years go by.
More and more people are going to variable speed, so its price should drop some since they will be in higher quantity.
Also, the gov is fixing to up the minimum effeciency to 13 seer. I got a feeling alot of manufacturers are going to go to the variable speed so they can squeeze out the higher seer ratings. (variable speed uses less electricity to operate which equates to higher seer)

Be sure to get a 10year extended warranty.... no matter what effeciency you decide on getting though.

The 2 stage gas heat would give you a nice increase in comfort.
Imagine driving down the road and setting the cruise control.
What if your car got up to speed and let off the gas completely, then when it slowed down.... it floored it.
Now imagine your cruise control set, and when the car slows down.... it adjusts the pedal halfway.
Most of the time, your heating unit will only need to run on the first stage. It will only kick into the high speed (if its set up with a two stage stat) only when it needs to (extreme cold weather), sorta like if you car was going up hill and needed to give it extra gas to get up and over.


This might help offset some costs as well....
http://trane.com/Residential/News/Rebate.aspx
Check with your trane dealer for more info on that.

Check with your utility provider... they might have a program such as this one....
http://www.energyright.com/index.htm

Here is a good chart that you can figure up how much you'll save on your utilities...
http://trane.com/Residential/Getting...cySavings.aspx

Be sure to get several estimates...
http://trane.com/Residential/DealerInfo/DealerInfo.aspx

[rabadger]

You need to ask yourself when the windows, doors and insulation will be done. If you update the equipment with new that is sized for the current conditions and then do windows, doors walls and attic the new equipment could end up oversized three or four years down the road. You need two sets of load calculations done. One set for what you have and another set for what it will be after windows, doors, and insulation. Without that info you are just guessing. You must see if the old equipment can be used with a zoning system and ducts to the addition. If it can be done then do the addition and windows, doors and insulation. When you are finished put in the right equipment to match the load. When you have them do the load calculations have them done room by room. That will tell you other potential problems that you may have with the duct work.

[bornriding]

Will never recover your money on anything over 13 seer.
May be a tad more comfortable, but for me definitely not worth the money.

[baffin789]

Bornriding, your assuming energy prices stay the same over the next 15 years. Fuel oil, natural gas, and even delivered coal prices (in some instances)have doubled over the last year and a half. Almost all new electrical generation built in the last 10 years has been natural gas fueled. Watch what happens as long term fuel buying contracts begin to expire in the future. JP you could pay out a 14seer quicker than you think.

[rabadger]

Is there any special reason why you can't go with one unit and zoning? It should be less expensive all around. It seams to me if that is a possibility you could get the best of both worlds. High eff. zoning and less cost on bi-yearly preventive maintenance. Remember - it costs a company man hours to clean and check two pieces of equipement. Try and keep one unit out of the attic. I do not know any installers or sevice people that like attic installations.

If you think you will get hot and cold spots no matter what you do thats exactly what you will get. Look at the good points of total system design. If it is designed for even temperature and zoned the hot and cold spot problem should be kept to a reasonable state. The only way total temperature control can be warrantied is if a thermostat is in every room and that is way to much overkill. There should be a way to zone it and keep temperatures under control.

[jp_nc]

Thanks for all the great info, folks. To answer some of the questions, we are in south central NC, so we've got a lot more cooling needs than extreme heating needs. Our power bills aren't too bad. Electric averages about $85/mo during the summer and gas bill averages $120 in the winter. But, of course, the house is generally too hot or too cold, depending on the season.

The house is about 2200 sq ft now, adding about 450 sq ft. Current system is a commercial package unit, about 7 yrs old, bought by previous owner on a scratch and dent sale, I think, with poorly placed ducts. Upstairs, 3 of the 4 rooms have the vents behind doors, so if you keep the door to the room open, it blocks the airflow. That's probably the primary reason for putting a unit in the attic - so we can put new ductwork in which will come down through the ceiling. I know that is not necessarily the most efficient setup, but reusing the existing ductwork seems like a bad idea. (This isn't all my idea, either - the 2 HVAC guys that bid the job so far suggested this as well.)

We expect to stay in this house for many years, so we've got plenty of time to recoup the costs. Also, I totally believe in buying the best you can afford for long term, "durable goods". But to me that means buying the best constructed and warranteed, with the best record of durability. It does not mean buying the fanciest, or the latest technology, unless that's really the best value for the money. That is my real dilemma – are the higher efficiency units really the best value for the money?

BTW, slinedawg, we have very ordinary tubs and faucets ;-)

[wormy]

Originally posted by rabadger
You need to ask yourself when the windows, doors and insulation will be done. If you update the equipment with new that is sized for the current conditions and then do windows, doors walls and attic the new equipment could end up oversized three or four years down the road. You need two sets of load calculations done. One set for what you have and another set for what it will be after windows, doors, and insulation. Without that info you are just guessing. You must see if the old equipment can be used with a zoning system and ducts to the addition. If it can be done then do the addition and windows, doors and insulation. When you are finished put in the right equipment to match the load. When you have them do the load calculations have them done room by room. That will tell you other potential problems that you may have with the duct work.

Sounds like this is a good option to me.

7 year old unit aint old enough to throw out just yet hehe.
Since your remodeling... try your best to have a closet that lands on top of another closet. Have a duct going from under house to attic to feed upstairs running through the closet.
Put in zone system to control airflow.

Your contractor will need to do a load based on zoning the equipment to see if it will work. Or at least get you by.

I bet you can take the money you save and invest in you some insulation and at least get a start on windows.

I generally don't like equipment in the attic if at all possible. Drain probs, techs working in hot attics, and so on.

Upgrading the duct system, zoning, attic insulation, wall insulation, windows.
Sounds like a great start.

With the bills you are describing.... it don't sound like you need supper high effeciency stuff.
I love the variable speed in the 14 seer but sounds like you'd be better off not going over a 12 for now.
BUT... they are fixing to change the minimum seer... so when that happens... go with the low end of 13 hehe.

From the sound of it... your duct system is definately screwed up. The supply vents should generally be under the windows along the outside wall. Not next the door on interior walls.

I wonder if that scratch and dent unit aint already oversized for the house.... and if you zone it out, it will end up being sized correctly and fixing the duct will be all you need to do to make it comfy.
I wouldn't be surprised if you heating and cooling bills arent' real close to what you have once you get it fixed up.



(getting sleepy.... hope my grammer is still in tact)